/* Calculator.h
Copyright (c) 2008 Michael Zahniser
Please note the license terms (MIT license) at the end of this document.

Header file for the Calculator class, which takes a stack of values and
a string representing an operation, and performs that operation on the stack.
*/

#ifndef __MZ_CALCULATOR_H__
#define __MZ_CALCULATOR_H__

#include "State.h"

#include <string>
#include <vector>



class Calculator {
public:
	// Constructor.
	Calculator();
	
	// Apply the named operation to the given stack.
	void operator()(const std::string &word);
	
	// Get the size of the stack.
	int Size() const;
	// Get the given stack entry, converted to text.
	std::string operator[](int index) const;
	
	// Get the error string from the last operation.
	std::string Error() const;
	
	// Duplicate the current state.
	void CopyState();
	// Get the current state.
	State &GetState();
	const State &GetState() const;
	
	// Retrieve command history.
	std::string Previous() const;
	std::string Next() const;


private:
	void Do(const std::string &word, int recursion = 0);
	
	
private:
	std::vector<State> states;
	std::vector<State>::iterator state;
	
	std::vector<std::string> history;
	mutable std::vector<std::string>::const_iterator historyIt;
	
	std::string error;
};



#endif

/* Copyright (c) 2008 Michael Zahniser

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE. */
